Table 2.

Technical properties of inhalation allergen chambers (based on Day et al.) [12]

Parameters	VCC (Vienna University Clinic) [11]	EEU (UK) [12]	Allergy Center (Vienna) [13]	VCC (Copenhagen) [14]	VCC (Atlanta) [15]	VCC (Hannover) [16]
Area [m2]	13.78	303	21	5	360	47
Height [m]	2.7	2.74	2.8	2.6	3.6	2.8
Number of subjects	14	160	24	1	150	18–25
Type of room	A custom designed room	A custom designed room in a hospital	A custom designed room	A portable tent	A custom designed room	A custom designed room
Ventilation system	Air pumped into the room through a ceiling-mounted system and removed through the	100% of outdoor air filtered by Farr 30/30 and Farr Riga-Flo 200 filters	Air pumped into the room through a ceiling-mounted system and removed through the floor	Vent filters, application of an allergen by means of a diffuser at a rate of 4000–6000 l/h	Outdoor ventilation at a rate of ≥ 5 cfm/person	Outdoor ventilation with a HEPA filter
Dose	1500 seeds/m3 (700–110 ng/m3) 20–110 ng/m3 Der p 1	3500 ±500 seeds/m3	1400 seeds/m3 90 ng/m3 Der p 1	50–100 ng/m3 Der p 1	3000–4500 seeds/m3	1000–8000 seeds/m3
Allergen concentration monitoring method	Bucard device, every 5 min	Rotorom device, every 30 min	Every 5 min	A portable measurement device installed in the filter	Bucard device, every 30 min	Rotorom device, every 30 min; a particle counter laser device, every minute